Molecular dyes composed of electron donors capable of photo-induced electron transfer to linked acceptors have been used to mimics the natural photosynthetic reaction centers in photochemical devices. Porphyrins are among the most employed building blocks as electron donors [1]. Intriguing is the system formed by metallo-porphyrins directly attached to fullerenes, actually realized in co-crystallites and solution form only [2], for which the typical fluorescence decay of the excited porphyrins is strongly quenched [3], i.e. non-radiative decay channels are favored. Next step toward an efficient solar cell is the deposition of similar metallo-porphyrin/fullerene systems on substrates, with the ability to control and tailor the orientation of both molecules (geometric structure and arrangement of the molecules are responsible for the physical properties of the system). Here, we demonstrate that the UHV deposition of porphyrins and C70 molecules on clean substrates allows the formation of films having selected intermolecular interactions and electronic properties. Using polarization-dependent x-ray absorption and photoemission spectroscopy we have investigated the growth, molecular orientation and electronic properties of Zn-Tetraphenyl-porphyrin (ZnTPP)/C70 films deposited on Ag(110), Si(111) and TiO2(110). The quite strong ZnTPP-fullerene interaction allows the growth of a single ZnTPP layer on top of a C7 monolayer (and vice versa), as well as it allows the self-assembling of the two molecular species in ordered multilayer structures when co-deposited. The interactions with the substrate and with C70 modify the ZnTPP electronic states, indicating formation of bonds and charge redistribution. Resonant photoemission, which probes the delocalization (charge transfer) of an excited electron on the time scale of the core-hole lifetime [4], indicates that the ZnTPP/C70 mixed systems delocalize more efficiently the excited electrons as compared to pure ZnTPP films. The charge transfer time depends on the empty �€* state in which the electron is excited and on the relative molecular orientations, but in general is below 10 fs and in some cases faster than 5 fs.